E87 rear brakes not functioning

[dabp]

Hi all,



About a month ago I went to start my car and noticed that the brake pedal didn't engage like normal, it travelled about halfway down before engaging. I checked the brake fluid reservoir and it was empty. I filled it, put out cardboard under the car and starting pumping the brake pedal. Nothing leaked out, and the level in the reservoir stayed consistent.

The car only brakes on the front wheels.

It's currently sitting in an autoshop, but the mechanic called and said he didn't really know what was wrong and didn't want to start just exchanging parts, since it's an old car with 400k km on the clock, and I don't want to just throw excessive amounts of money at it.

Does anyone know if this is something regular to happen and if so can give a hint as to what the mechanic can check/exchange to get her up and running again?



E87 LCI '07 118D

[BMWCCA1]

Manual or automatic?

[dabp]

Originally Posted by BMWCCA1

Manual or automatic?

Automatic.

Does that have anything to do with the brake system?

[dabp]

Originally Posted by BMWCCA1

Manual or automatic?

Since you are the only one to respond so far, I hope it's ok to responds twice to this message, because I was puzzled as to the question.

Could you perhaps find time to elaborate on why you asked if it was manual or automatic? To my knowledge, this doesn't make any difference in the brakesystem and the manuals I have found, list the same parts, regardless of engine or transmission system.

[BMWCCA1]

I can't really reply because it's been so long since your first post and you've edited your post. You must have originally included some description of the failure mode beyond just the fluid loss and perhaps I assumed it could involve the stick-shift car's hill-holder mode where the rear brakes hold for a few seconds after releasing the brake and while engaging the clutch. We know you lost fluid and that the pedal went too far down, but the fluid had to go somewhere and how can you tell that only the front brakes are working?

My thought process may have gone to the brake fluid as it supplies the clutch cylinders, too, which generally take their feed from the brake-fluid reservoir about half-way down and when either cylinder leaks, the reservoir will drop. But even then you should be able to see where the fluid went.

But then we now know you have an automatic. It seems what you need is a better mechanic. Especially if it's been sitting at the shop for a month and they've gotten nowhere!

[dabp]

Originally Posted by BMWCCA1

I can't really reply because it's been so long since your first post and you've edited your post. You must have originally included some description of the failure mode beyond just the fluid loss and perhaps I assumed it could involve the stick-shift car's hill-holder mode where the rear brakes hold for a few seconds after releasing the brake and while engaging the clutch. We know you lost fluid and that the pedal went too far down, but the fluid had to go somewhere and how can you tell that only the front brakes are working?

My thought process may have gone to the brake fluid as it supplies the clutch cylinders, too, which generally take their feed from the brake-fluid reservoir about half-way down and when either cylinder leaks, the reservoir will drop. But even then you should be able to see where the fluid went.

But then we now know you have an automatic. It seems what you need is a better mechanic. Especially if it's been sitting at the shop for a month and they've gotten nowhere!

It was just a spelling mistake I corrected, I didn't change anything about the description of the issue.

Mechanic said that depressing the pedal only engaged the front brakes.

I told the mechanic that he didn't need to rush, I rarely drive, work from home etc.

[dabp]

Just an update:

The car is fixed, it was a problem with the rear calipers and they have now been changed plus the system has been bled.